Publication Date:
2016-01-02
Description:
We present the results of a study of the amount and distribution of cold atomic gas, as well its correlation with recent star formation in a sample of extremely faint dwarf irregular galaxies. Our sample is drawn from the Faint Irregular Galaxy GMRT Survey (FIGGS) and its extension, FIGGS2. We use two different methods to identify cold atomic gas. In the first method, line-of-sight H i spectra were decomposed into multiple Gaussian components and narrow Gaussian components were identified as cold H i . In the second method, the brightness temperature ( T B ) is used as a tracer of cold H i . We find that the amount of cold gas identified using the T B method is significantly larger than the amount of gas identified using Gaussian decomposition. We also find that a large fraction of the cold gas identified using the T B method is spatially coincident with regions of recent star formation, although the converse is not true. That is only a small fraction of the regions with recent star formation are also covered by cold gas. For regions where the star formation and the cold gas overlap, we study the relationship between the star formation rate density and the cold H i column density. We find that the star formation rate density has a power-law dependence on the H i column density, but that the slope of this power law is significantly flatter than that of the canonical Kennicutt–Schmidt relation.
Print ISSN:
0035-8711
Electronic ISSN:
1365-2966
Topics:
Physics
